A DFT study of electronic structures, energies, and molecular properties of lithium bis[croconato]borate and its derivatives

Theoretical studies on electrolyte salts, lithium bis[croconato(2-)]borate (LBCB) and its derivatives, lithium [croconato(2-) salicylato(2-)]borate (LCSB), and bis[salicylato(2-)]borate (LBSB) are carried out using density functional theory (DFT) method and B3LYP theory level for the first time. Bidentate structures involving two oxygen atoms are preferred. Based on these conformations, a linear correlation was observed between the highest occupied molecular orbital (HOMO) energies and the limiting oxidation potentials measured by linear sweep voltammetry, which supports experimental results that strongly electron-withdrawing substituent anions are more resistant against oxidation than their organic counterparts. The correlations were also observed between ionic conductivity and binding energy, solubility and theoretical set of parameters of anion, thermal stability and the hardness (η). Wave function analyses have been performed by natural bond orbital (NBO) method to further investigate the cation–anion interactions.